1. Field of the Invention
This invention relates to prefabricated railing systems adapted for use on staircases having virtually any pitch angle.
2. Discussion of the Related Art
Each staircase has a pitch angle of its own. This angle is determined by the rise (height of the top of one stair tread to the top of the next stair tread) and the run (depth of the stair tread from the face of one rise to the face of the next rise). There are incalculable numbers of combinations which result in many pitch angles. Prefabricated railings have been produced for many years, but with a major drawback. They must be cut to the precise angle of the stair for which they are intended. If for any reason the stair is not installed perfectly level, the angle is wrong. The result is that the railing follows either a greater or lesser angle than the stair or that the railing must be installed so that the newel post and/or balusters are not placed perfectly vertical.
Various hand rail systems have been suggested. For instance, U.S. Pat. No. 2,870,996, issued Jan. 27, 1959, to Helt, shows a system having a plurality of vertically extending tubular spindles provided in spaced, parallel relationship. The top ends of the spindles are pivotally connected to a top rail and the bottom ends are pivotally connected to a bottom rail. U.S. Pat. No. 3,804,374, issued Apr. 16, 1974, to Thom, shows a twin post railing system having pairs of laterally spaced post members. Each pair of posts has a vertically adjustable clamp mechanism extending laterally therebetween. Both the posts and the clamp mechanisms are cut from extruded metal pieces for inexpensive manufacture. An offset hand rail is angularly adjustably mounted upon one of the clamp mechanisms of each pair of posts. U.S. Pat. No. 3,414,236, issued Dec. 3, 1968, to Siegal, shows a foldable hand rail in the form of a downwardly opening channel having side walls diverging at their ends, the inside of which form wedging surfaces. The diverging side walls engage outwardly extending feet of an inner channel, pivoted to the pickets of the hand rail.